Effects of added fruit polyphenols and pectin on the properties of finished breads revealed by HPLC/LC-MS and Size-Exclusion HPLC

The positive roles of fruit polyphenols (PPs) and dietary fibres (DFs) in promoting human health and well-being are now well recognised. This study investigates the effects of added fruit PPs and pectin on the composition and extractability of PPs and proteins from finished breads, and complements our recently published papers that focus on the rheological and physicochemical properties of breads containing added PPs and pectin. Breads were prepared in the absence or presence of a high methoxyl (HM) apple pectin and kiwifruit, blackcurrant or apple PP extract, and subjected to texture measurements (crumb firmness), informal sensory evaluations and chemical analyses. An epicatechin standard was also used in place of the fruit PP extract to estimate the extractability and recovery of PPs from bread. Results show that adding a PP extract and pectin to bread modified bread firmness, specific volume, recovery of added PPs, amount of free thiol groups of bread proteins, and also the extractability of PPs and proteins from bread. The recovery of added PPs was the lowest for the APE + HM pectin bread which had the highest bread firmness. High performance liquid chromatography (HPLC)-mass spectrometry (MS) PP profiling revealed that baking caused oxidation of some added PPs such as quercetin and myricetin. Size-Exclusion HPLC analysis showed that adding a combination of PP extract and HM pectin decreased the S–H group concentration and increased the percentage of the Unextractable High Molecular Weight (UHMW) proteins, compared to the control bread. The added pectin and PPs, and possibly the oxidation products of the added PPs, affected the interactions between water and bread components (such as gluten proteins) during dough development and bread baking, causing differences in bread cross-linking microstructure and textural properties, which ultimately influenced the extractability and/or stability of added PPs.     

Properties of bread dough with added fiber polysaccharides and phenolic antioxidants: a review

During breadmaking, different ingredients are used to ensure the development of a continuous protein network that is essential for bread quality. Interests in incorporating bioactive ingredients such as dietary fiber (DF) and phenolic antioxidants into popular foods such as bread have grown rapidly, due to the increased consumer health awareness. The added bioactive ingredients may or may not promote the protein cross-links. Appropriate cross-links among wheat proteins, fiber polysaccharides, and phenolic antioxidants could be the most critical factor for bread dough enhanced with DF and phenolic antioxidants. Such cross-links may influence the structure and properties of a bread system during baking. This article presents a brief overview of our current knowledge of the fate of the key components (wheat proteins, fibers, and phenolic antioxidants) and how they might interact during bread dough development and baking.     

Sensory and physical quality characteristics of bread fortified with apple pomace using fuzzy mathematical model

Apple pomace, after different processing procedures, was added into wheat flour in bread production to improve the dietary fibre content of breads. A fuzzy mathematical model was used in the sensory assessment of bread to improve the reliability of final conclusion. The addition of both apple pomace (AP) and skimmed apple pomace (SAP) reduced the extensibility and improved the resistance of wheat dough compared to the control sample. Wheat dough fortified with apple pomace of differing particle sizes did not have significant effects on either farinograph properties or extensograph properties. Sensory assessment of bread based on fuzzy mathematical model indicated that optimum concentration of apple pomace, both AP and SAP, added into wheat dough was 3%. Such results may be of importance when considering the use of apple pomace in bread production so as to enhance the dietary fibre intake, and also improve the sensory properties of bread.     

Exploring the interactions between blackcurrant polyphenols, pectin and wheat biopolymers in model breads; a FTIR and HPLC investigation

This study explores the interactions between added blackcurrant polyphenols (PPs) and pectin, as well as different bread components in model bread systems. A series of model breads containing flour, yeast, sugar, salt, oil and water, with/without added pectin and blackcurrant PP extract, were prepared and characterised. Results show that adding PPs in addition to pectin increased the total extractable PP content and antioxidant activity of the breads, and decreased the proportion of unextractable high molecular weight proteins (detected by size exclusion-HPLC). The composition of bread formulations influences the amount of anthocyanins, especially delphinidin-3-o-glucoside and delphinidin-3-o-rutinoside, which are retained after bread baking. Replacing flour with starch and gluten, adding blackcurrant PP extract and pectin, or removing bread components (oil, salt or the mixture of yeast and sugar), caused changes in the bread gluten conformations related to Amide I and II bands (revealed by FTIR), as well as the extractability of PPs and proteins (revealed by HPLC).     

Effects of flour from different barley varieties on barley sour dough bread

Twenty flours from 16 different barley varieties cultivated in 1990 and 1992, and a Swedish reference flour, were fermented by Lactobacillus plantarum A1 to sour doughs. Barley breads (40% barley/60% wheat flour) from each flour type were baked with and without an admixture of barley sour dough in order to investigate how the sour dough admixture would affect the baking properties. A trained panel carried out sensory evaluation by conventional profiling on breads made from three of the barley varieties and the Swedish reference flour, made with and without sour dough admixture.

The barley varieties influenced both the sour dough properties and the properties of the barley bread. The pH of bread with sour dough ranged from 4.6 to 4.8 as compared to 5.4 to 5.6 in bread without sour dough. The acidity of the breads with sour dough ranged from 4.1 to 5.0 ml NaOH/ 10 g bread crumb as compared to 2.4 to 3.6 in breads without sour dough. In 14 of the twenty bread types an addition of sour dough lowered the bread volume. Breads with a sour dough admixture scored higher for total taste and acidulous taste than breads without sour dough. The β-glucan content of the flours had no significant influence on the sour dough or the sensory characteristics of the bread, except for the breadcrumb colour.     

Structure and Dynamics of Wheat Starch in Breads Fortified with Polyphenols and Pectin: an ESEM and Solid-State CP/MAS 13C NMR Spectroscopic Study

Two sets of breads formulated with a 20% difference in water quantity in the absence (control bread), or presence (fortified bread) of high methoxyl pectin (HM) and an apple, kiwifruit, or blackcurrant polyphenol (PP) extract (APE, KPE or BPE) were examined by Environmental Scanning Electron Microscopy (ESEM) and Cross Polarization/Magic Angle Spinning ¹³C NMR Spectroscopy. ESEM revealed that all the bread doughs had similar microstructures, comprising starch granules and yeast cells embedded in a continuous gluten matrix. However, the microstructure of the finished breads differed. NMR studies revealed differences in amylopectin-related crystalline domains and the amylose-related amorphous domains among the breads. All the breads showed V-type or amorphous starch structures by NMR, and the control bread may also contain some A-type starch. Breads formulated with 20% extra water showed a greater degree of starch gelatinization, a smoother crumb microstructure, and a lower amorphous starch content. It is feasible to incorporate PPs and pectin in breads at reasonably high concentrations.     

Effects of genotype, location and baking on the phenolic content and some antioxidant properties of cereal species

In order to assess the effect of genotype, location and their interaction on total phenolic content (TPC) of chemical extracts, the whole grains of durum and soft wheat, oat, barley and triticale were evaluated. Data showed differences in phenolic content of chemical extracts among cereal species and the analysis of variance confirmed the key role of location. Besides TPC and trolox equivalent antioxidant capacity (TEAC) values assessed by chemical extraction were compared with those obtained with an in vitro digestive enzymatic extraction. Differences were found between methanolic and enzymatic extracts, and data confirmed that enzymatic technique enhanced extraction of antioxidants but pointed out lesser differences among cereal types. The breads obtained by flours enriched with different levels of bran were also evaluated. Chemical extracts highlighted the increasing levels of antioxidants according to bran enrichments, without pointing out changes caused by baking. The enzymatic extraction instead did not show differences regarding to bran enrichments, but documented a loss in antioxidant properties of breads in respect to corresponding flours. On the other hand the scarce differences between flours and corresponding breads did not allow asserting that baking modified the TPC and TEAC, independently of the extraction methods used. Indeed, during baking process, also the observed phenolic acids profile variations did not vary the antioxidant properties of breads.     

Quality characteristics improvement of low‐phenylalanine toast bread

This study was designed to prepare and evaluate low‐phenylalanine toast bread made from gliadin‐free wheat flour and hydrocolloids. Wheat protein fraction (gliadin) rich in phenylalanine was extracted using aqueous alcohol solution for the production of low‐phenylalanine wheat flour. Pectin, gum arabic and carboxymethylcellulose (CMC) were used separately to improve the quality of bread at levels of 1, 2 and 3%. Chemical, rheological, organoleptic, baking, staling and microstructure of bread were studied. Phenylalanine content of gliadin‐free bread samples reduced by 43.2% compared with control. Separation of gliadin negatively affected the rheological properties of dough and baking quality of bread, while rheological properties, baking quality and staling were improved upon hydrocolloids addition. Microscopic examination of crumb structure revealed remarkable differences in control and treated breads. It was found that acceptable bread could be produced using gliadin‐free wheat flour with the addition of pectin or CMC up to 2 and 3%, respectively.     

Effects of alkylresorcinols on volume and structure of yeast-leavened bread

BACKGROUND: Alkylresorcinols (AR) are amphiphilic phenolic compounds found in high amounts in wheat, durum wheat and rye, with different homologue composition for each cereal. The effect of different amounts of added AR from these cereals on bread volume, height, porosity and microstructure was studied. Breads with added rye bran (with high levels of AR) or acetone‐extracted rye bran (with low levels of AR) were also baked, as well as breads with finely milled forms of each of these brans. RESULTS: Breads with high amounts of added AR, irrespective of AR homologue composition, had a lower volume, a more compact structure and an adverse microstructure compared with breads with no or low levels of added AR. AR were also shown to inhibit the activity of baker's yeast. There was no difference in bread volume and porosity between bread baked with rye bran and acetone‐extracted rye bran or with brans of different particle size. CONCLUSION: Irrespective of homologue composition, AR had a negative effect on wheat bread properties when added in high amounts as purified extracts from wheat, durum wheat and rye. Natural levels of AR in rye bran, however, did not affect the volume and porosity of yeast‐leavened wheat breads. Copyright © 2010 Society of Chemical Industry     

Rheological properties of gluten-free bread formulations

In this study, the rheological properties of rice bread dough containing different gums with or without emulsifiers were determined. In addition, the quality of rice breads (volume, firmness and sensory analysis) was evaluated. Different gums (xanthan gum, guar gum, locust bean gum (LBG), hydroxyl propyl methyl cellulose (HPMC), pectin, xanthan–guar, and xanthan–LBG blend) and emulsifiers (Purawave^™ and DATEM) were used to find the best formulation for gluten-free breads. Rice dough and wheat dough containing no gum and emulsifier were used as control formulations. The rice dough containing different gums with or without emulsifiers at 25 °C showed shear-thinning behavior with a flow behavior index (n) ranging from 0.33–0.68 (except pectin containing samples) and consistency index (K) ranging from 2.75–61.7 Pa sⁿ. The highest elastic (G′) and loss (G″) module were obtained for rice dough samples containing xanthan gum, xanthan–guar and xanthan–LBG blend with DATEM. When Purawave^™ was used as an emulsifier, dough samples had relatively smaller consistency index and viscoelastic moduli values compared to DATEM. The viscoelastic parameters of rice dough were found to be related to bread firmness. Addition of DATEM improved bread quality in terms of specific volume and sensory values.     

Bioactive compounds in spelt bread

In this study the milling and baking characteristics of ten strains of spelt wheat (Triticum aestivum ssp. spelta) originated from Polish breeding were shown. Evaluation of the grain included test weight, vitreousness and hardness. White spelt flour with extraction rate of 65–70% was characterized through the analyses of ash, protein, wet gluten and starch contents as well as Farinograph test, Amylograph test and falling number. Most of spelt wheat varieties investigated demonstrated good milling properties and high baking quality. The spelt breads were analyzed for their potential beneficial components, including total phenolic compounds (TPC) and flavonoids (TF), tocopherols (T) and tocotrienols (T3), inositol phosphates (IP) and reduced (GSH) and oxidized (GSSG) glutathione, and then compared to commercial wheat roll based on wheat flour with extraction rate of approximately 70%. The comparison of the bioactive compounds content between spelt breads and wheat showed a similar level of TPC, TF and GSH. The tocopherols and tocotrienols content in spelt bread was about twice lower when compared to wheat roll. Moreover, spelt wheat bread formulated from flour originated from STH 915 strain showed higher content of inositol phosphates when compared to wheat roll and to those breads from flour of STH 975 and STH 974 strains.     

Effect of flaxseed and wheat flour blends on dough rheology and bread quality

The rheological and baking properties of flaxseed/wheat composite flours were studied. Flaxseed flour was used to replace 50, 100, 150 and 200 g kg^?1 of wheat flour in bread. Farinographic studies showed that water absorption, dough development time and mixing tolerance index increased as the amount of flaxseed flour increased, while dough stability decreased at 100, 150 and 200 g kg^?1 of flaxseed flour substitution. The extensographic energy of dough also decreased at 150 and 200 g kg^?1 flaxseed levels. The addition of increasing amounts of flaxseed flour caused a decrease in extensibility. Doughs containing 100, 150 and 200 g kg^?1 flaxseed flour showed resistance to extension comparable to that of control dough. The specific volume of flaxseed flour breads was similar to that of control bread. Crust L, a, b values of breads with flaxseed flour were lower than those of control bread. Breads with flaxseed flour gave lower crumb L and b values and higher a values than control bread. The sensory properties showed that an acceptable bread could be produced using flaxseed flour up to a level of 200 g kg^?1. Copyright © 2007 Society of Chemical Industry     

Application of FT-IR and Raman spectroscopy for the study of biopolymers in breads fortified with fibre and polyphenols

Adding dietary fibres (DFs) and polyphenols (PPs) to bread is a convenient way to deliver the health benefits of DFs and PPs to consumers. In this study, we investigate the interactions among added pectin polysaccharides, PPs and bread components such as wheat proteins in different bread formulations. Two sets of breads with a 20% difference in the water content were prepared in the absence (Control), or presence of pectin and/or fruit PP extracts (Treated). Results show that adding pectin and PPs caused changes in the molecular conformations and polymer structure of wheat gluten and starch in the finished breads, especially in the secondary protein conformation (Amides I and II, as revealed by FTIR Spectroscopy). An increase of water content during dough formulation also affected secondary protein conformation. The Treated breads gained β-sheets in the protein's secondary conformation at the expense of β-turns, and contained more un-ordered conformations especially in the presence of berry PPs. These results were confirmed by complementary Raman spectroscopic measurements. Both hydrophobic and H bonding interactions occurred among bread components and the added PPs and pectin, which affected PP stability during breadmaking and the total extractable PP content of finished breads. Schematic Loop and Train models for breads enhanced with PPs and pectin are proposed that illustrate the possible conformational changes in wheat protein structure due to the presence of added PPs and pectin.     

发酵麦麸对面包面团生化特征及烘焙学特性的影响

采用马克斯克鲁维酵母(Marx Kluyveromyces)发酵麦麸,通过生化分析、流变特性测试及微观结构观察(Scanning electron microscope,SEM)等多种分析手段,研究其对面包面团生物化学特征和烘焙学特性的影响。结果表明:马克斯克鲁维酵母发酵麦麸中富含多种天然酶,主要包括纤维素酶、木聚糖酶和阿魏酸酯酶;水解酶在面包制作过程中持续作用,促进木聚糖溶解和酚类化合物释放,赋予面包较高的营养价值;与仅添加木聚糖酶的麦麸面包面团相比,马克斯克鲁维酵母发酵麦麸面包面团具有更好的持气性及连续的面筋网络结构,面包全质构特性和比容显著提升。研究结果显示,马克斯克鲁维酵母发酵麦麸可以作为一种天然面包功能配料。     

Influence of sorghum flour addition on flat bread in vitro starch digestibility,antioxidant capacity and consumer acceptability

Wheat flour (WF) flat bread was prepared with varying levels of wholegrain “white” sorghum flour (WSF) or “red” sorghum flour (RSF). Farinograph dough rheology indicated reduced water absorption and stability time and increased breakdown with increased sorghum flour addition. The total phenolic content and antioxidant capacity of the 40% RSF flat bread >40% WSF flat bread > control (100% WF) flat bread. The rapidly digestible starch (RDS) level was lower in the 40% WSF and 40% RSF flat breads than the control (100% WF). Hedonic sensory evaluation indicated that sorghum addition did not reduce the sensory preference for the flat breads. Human clinical studies are now required to determine if the lower levels of RDS and higher antioxidants observed in the sorghum containing flat breads translate into beneficial low glycemic index and reduced oxidative stress in vivo.     

Influence of genotype and protein content on the baking quality of hearth bread

The relationships between protein content and quality and the loaf characteristics of hearth breads made from the respective flours were investigated for 20 wheat genotypes, comprising both commercially grown cultivars and advanced breeding lines, grown in 1997 and 1998. In both years the average protein content was increased by increasing the level of nitrogenous fertiliser application, this effect being more pronounced in 1997 than in 1998. Grain samples were milled and evaluated for endosperm hardness, protein content, SDS sedimentation volume, mixing properties and baking quality determined by a hearth bread baking test using optimal mixing and fixed proving time. When producing hearth bread, both the form (height/width) ratio and loaf volume are critical external characteristics. Genotype differences, mainly due to differences in protein quality, were more important for both form ratio and loaf volume than differences in protein content. The dough development time of the Farinograph, operated at high speed (126 rev min^?1), was the best indicator of heart bread baking quality, giving high positive correlations to both the volume (r = 0.89) and form ratio of the loaf (r = 0.90). Climatic differences between the two years, in particular temperature during ripening, also affected the quality parameters studied. Copyright © 2004 Society of Chemical Industry     

Effect of Yeast Extracts Containing Propionic Acid on Bread Dough Fermentation and Bread Properties

ABSTRACT: Three commercial yeast extracts (Oxoid, Champlain, Lallemand) fermented with immobilized cells of Propionibacterium freudenreichii were added in broths and bread formulations, and their effect on growth and gas production by bakers yeast was determined. Appearance and preservation of the breads were examined. There was significantly more gas produced by the yeast when fermented yeast extracts were added to the dough. In broths, the initial growth rate was slower with media containing fermented yeast extract when compared to their unfermented equivalents. Loaves formulated with propionic acid of the fermented yeast extract contained less ethanol. Paired t-tests showed that breads formulated with fermented yeast extract were protected for a longer period against mold than those that contained non-fermented yeast extract.     

Performance of mechanically developed dough in pita bread production

The feasibility of adapting a mechanical dough development process, using a high speed mixer (Tweedy-35), to pita bread production was studied 'on line' at a commercial, traditional pita bakery.
A satisfactory pita bread was produced from a mechanically developed dough under the following conditions: work input 5.5 Whr/kg dough (mixing time 2 min), 3% yeast, 55% water absorption, dough temperature 30°C, no oxidizing agents and intermediate proofing (between mixing and dividing) of 10 min. The advantages of the mechanical over the conventional process were: increase in water absorption by 10%, which brought about a proportional gain in product yield per unit weight of flour; and reduction in holding floor time from 40–60 min to 12 min.
The baking performance of the pita bread under different controlled conditions gave insight into the mechanisms involved in the baking process, especially the relationship between dough mechanical properties and heat transfer during baking.     

百香果皮果胶提取工艺及其对面团和面包品质的影响

从百香果皮中提取果胶作为面包改良剂,以未添加改良剂和添加豆渣的面团为对比,通过质构仪分析百香果皮果胶对生面团延展性和面包坚韧性的影响。结果显示:百香果皮果胶提取的最佳工艺条件为:质量分数为0.45%的草酸铵、料液比1∶45(g/mL)、50 W超声波辅助提取90 min,果胶提取率为24.79%。质构测试结果表明:添加百香果皮果胶的面团拉丝长度、弹性、粘性和内聚性较大,而硬度较小,其面团品质最好。添加豆渣和百香果皮果胶均使面包的硬度和咀嚼性降低,有效改善面包的质构特性。Kramer感官评定结果表明百香果皮果胶面包最受消费者喜爱。     

番木瓜保健面包的研制及营养成分分析

为了研究开发甜面包口味多样性、营养保健性和番木瓜资源的综合利用,在面团中添加番木瓜果肉,经过搅拌、发酵、烘烤制成营养齐全、对人体具有保健作用的水果面包;通过正交试验并确定番木瓜面包的最佳配方,即添加番木瓜泥50%,水20%,酵母1.6%,发酵100 mn;同时对番木瓜面包中胡萝卜素、VC、总果胶营养成分含量进行测定,结果表明番木瓜面包比普通面包胡萝卜素增加了8.3倍、VC增加了3.86倍、总果胶增加了4.74倍.